N-fluoroalkyl-sulfonamides and process for preparing them

ABSTRACT

NEW STABLE SULFONAMIDES CONTAINING A CF2 GROUP ADJACENT TO NITROGEN ARE OBTAINED BY REACTING N-MONO-SUBSTITUTED SULFONAMIDES WITH FLUORO-OLEFINS OR THE ALKALI METAL SALTS OF SAID SULFONAMIDES WITH FLUORO-HALOALKANES. THE PRODUCTS ARE USEFUL AS REACTIVE INTERMEDIATES FOR A VARITETY ORGANIC SYNTHESES AND-OWING TO THEIR POLARITY AND HIGH BOILING POINTS-AS VALUABLE SOLVENTS FOR SPARINGLY SOLUBLE ORGANIC OR INORGANIC COMPOUNDS.

United States Patent 3,708,538 N-FLUOROALKYL-SULFQNAMIDES AND PROCESSFOR PREPARING THEM Helmut Hahn, Burghausen, Salzach, Ottto Seherer, Bad

Soden, Taunus, and Siegfried Rebsdat, Altottiug, Germany, assiguors toFarbwerke Hoechst Aktiengesellschaft vorrnals Meister Lucius & Bruning,Frankfurt am Main, Germany No Drawing. Filed July 29, 1970, Ser. No.59,363 Int. Cl. C07c 143/74, 143/78 US. Cl. 260-556 A 4 Claims ABSTRACTOF THE DISCLOSURE New stable sulfonamides containing a CF group adjacentto nitrogen are obtained by reacting N-mono-substituted sulfonamideswith fluoro-olefins or the alkali metal salts of said sulfonamides withfluoro-haloalkanes. The products are useful as reactive intermediatesfor a variety of organic syntheses and-owing to their polarity and highboiling points-as valuable solvents for sparingly soluble organic orinorganic compounds.

The present invention relates to novel Nafluoroalkyl sulfonamides andprocesses for preparing them.

It is known that fluoro-olefins, for example trifluorochloroethylene,tetrafiuoro-ethylene or difluoro-chloroethylene can be added onalcohols, amines, diamines or even oximes to yield, for example,products that carry two fluorine atoms linked to the carbon atom inadjacent position to the nitrogen atom, the bond being, however, so weakthat they already react with hydrogen cyanide to yield a dinitrile andhydrogen fluoride (as disclosed in US. Pat. No. 2,883,388) or with coldwater to yield the corresponding carbonamide and hydrogen fluoride:

(I. Am. Chem. Soc. 72, p. 3649 (1950), Preuttetal).

It has now been found that stable fiuorinated compounds having a C-Fgroup adjacent to the nitrogen are obtained by reacting fluoro-olefinswith N-alkyl or N- aryl-sulfonamides in the presence of alkalis:

In this reaction equation R stands for alkyl or an unsubstituted orsubstituted aromatic radical, R for an aliphatic radical containing 1 to12 carbon atoms, a cycloaliphatic radical or a substituted orunsubstituted aromatic radical, X for hydrogen, fluorine, chlorine orbromine, Y for fluorine, chlorine or bromine or a periiuorinatedaliphatic radical, for example CE The alkalis used for the abovecondensation may be alkali metal hydroxides or alkali metals.

As sulfonamides there may, for example, be used: =N- alkylphenylsulfonamides such as N-methyl, N-ethyl, N- butyl or N-dodecyl-benzenesulfonamide, the corresponding compounds substituted in the phenylnucleus, such as N-alkyl-chlorophenyl sulfonamide orN-alkyl-nitrochlorophenyl sulfonamide or .N-alkyl-aminophenylsulfonamide. N-cycloalkyl sulfonamides or N-aryl sulfonamides maylikewise be used, for example toluene-sulfanilide. Finally,N-fluoroalkyl sulfonamides may also be prepared from correspondingaliphatic sulfonamides, for example N- methyl-methyl-sulfonic acid amideor N-butyl-propyl-sulfonic acid amide. Upon reaction with alkali metalhydroxide in water or alcohol all these sulfonamides easily yield thecorresponding alkali metal salts.

3,708,538 Patented Jan. 2, 1973 in which Me stands for an alkali metalsuch as sodium, potassium or lithium and Z for chlorine or bromine, andR, R, X and Y are defined as above.

As fiuoroalkanes that can be converted into fluoroolefins there may bementioned, above all: 1,2-difiuoro- 1,2,2-trichloroethane, 1,1,2trifluoro-1,2-dichloroethane, 1,1,2,2-tetrafluoro-l-bromoethane as wellas 1,1,l,2,3,3- hexafluoro-3-bromo-propane.

The reactions of the invention are preferably carried out in polarsolvents; dimethylformamide or dimethylsulfoxide has proved especiallysuitable. The sulfonamide is dissolved in these solvents, a small amountof alkali is added and the reaction which in most cases is exothermic,is started by introducing the fiuoro-olefin. According to the othermethod of the invention, the alkali metal salt of the sulfonamide isdissolved in one of the above $01- vents and one of the abovefluoro-halo-alkanes is added dropwise, whereupon an alkali metal halideis formed as a by-product.

The simple addition of fluoro-olefins on sulfonamides to be generallyeffected at normal pressure is surprising since it could not be expectedthat the strongly acid hydrogen atom of the sulfonamide would react aseasily as disclosed above and thus open the way to the stable N-fluoroalkyl sulfonamides. I

The so-obtained N-fluoroalkyl sulfonamides are novel stable compoundsthat can be used as valuable reactive components for the manufacture ofdyestuffs, pharmaceuticals, pesticides or textile auxiliaries. In viewof their distinct polarity and owing to their high boiling points thenew compounds are valuable solvents for sparingly soluble inorganic andorganic compounds, e.g. betaines and EXAMPLE 1 0.3 g. of sodium wasadded to a solution of 93 g. of N-ethylbenzene sulfonamide in 250 ml. ofdimethylformamide and then a gas stream of trifluoro-chloroethylene wasfed in until no more olefin was absorbed. The temperature rose to 50 C.and the reaction was complete after 1.5 hours. The reaction product wasthen introduced into water, the organic phase was taken up with 300 ml.of methylene chloride and the methylene chloride extract was shaken withsodium hydroxide solution and water.

After drying over sodium sulfate the methylene chloride was evaporated.107 g. of a crude product were obtained, from whichN-ethyl-N-trifluoro-chloroethyl-benzene sulfonamide was distilled in anamount of 82 grams. Boiling point 136138 C. under 2 torr.

Elementary analysis.C I-I ClF NO S (molecular weight: 301.5). Found(percent): N, 4.9; Cl, 11.5; F, 18.5. Calculated (percent): N, 4.7; Cl,11.8; F, 18.9.

EXAMPLE 2 1 g. of sodium was added to a solution of 100 g. ofN-ethyl-p-methyl-phenyl sulfonamide in 200 ml. of dimethylformamide andthe mixture was treated as disclosed in Example 1 withtrifiuoro-chloroethylene and worked up in the same manner. 176 g. ofcrude products were obtained, from which 125 g. ofN-ethyl-N-trifiuoro-chloroethyl-p-methylphenyl sulfonamide weredistilled. Boiling point: 148152 C. under 1 to 2 torr.

Elementary analysis.C H-;Cl F NO S (molecular weight: 315.5). Found(percent): N, 4.5; CI, 11.4; F, 17.9. Calculated (percent): N, 4.4; Cl,11.3; F, 18.2.

EXAMPLE 3 As disclosed in Example 1, 80 g. ofN-methyl-3,4-dichlorophenyl sulfonamide in 100 ml. of dimethylformamidewere reacted with trifiuoro-chloroethylene in the presence of 1 g. ofsodium. The temperature rose to 60 C. After the usual working upaccording to Example 1, 104 g. ofN-methyl-N-trifluoro-chloroethyl-3,4-dichlorophenyl sulfonamide wereobtained. Boiling point: 155- 156 C. under 0.4 torr.

Elementary analysis.C H Cl F NO S (molecular weight: 356.5). Found(percent): N, 4.5; CI, 11.8; F, 18.7. Calculated (percent): N, 4.7; CI,11.8; F, 18.9.

EXAMPLE 4 From 93 g. of N-methyl-p-methylphenyl sulfonamide in 100 ml.of dimethylformamide and 1 g. of sodium, 124 g. ofN-methyl-N-trifluoro-chloroethyl-p-methyl-phenyl sulfonamide wereobtained according to the method disclosed in Example 1. Boiling point:142-144 C. under 1.6 torr.

Elementary analysis.-C H CIF NO S (molecular weight: 301.5).Found(percent): N, 4.5; Cl, 11.8; F, 18.7. Calculated (percent): N, 4.7; Cl,11.8; F, 18.9.

EXAMPLE 5 132 g. of N-ethyl-p-methylphenyl sulfonamide were dissolved in150 ml. of dimethylformamide and 1.2 g. of sodium were added. At 50-60C. 100 g. of perfluoro propene were fed in Within about 2.5 hours. Afterthe work-up as disclosed in Example 1, 153 g. of N-ethyl-N-hexafluoropropyl p methylphenyl sulfonamide were obtained. Boilingpoint: 132-134 C. under 0.7 torr.

Elementary analysis.C H F NO S (molecular weight: 349). Found (percent):N, 4.3; F, 32.2. Calculated (percent): N, 4.0; F, 32.7.

EXAMPLE 6 55 g. of N-methyl-methane sulfonamide were dissolved in 100ml. of dimethylformamide and 1 g. of sodium was added.Trifiuoro-chloroethylene was fed in until no more olefin was absorbed.The temperature rose to 78 C. Stirring was continued for 0.5 to 1 hourand then the product was worked up as disclosed in Example 1. 85 g. ofN- methyl-N-trifluoro-chloroethylmethane sulfonamide were obtained.Boiling point: 7073 C. under 1.3 torr.

Elementary analysis.C H ClF NO S (molecular weight: 225.5). Found(percent): N. 6.8; C], 15.8; F, 25.3. Calculated (percent): N, 6.2; Cl,15.8; F, 25.0.

EXAMPLE 7 85 g. of 1,l-difiuoro-1,2,2-trichloroethane Were addeddropwise within about 30 minutes to a solution of 145 g. of the sodiumsalt of N-methyl-3,4-dichlorophenyl sulfonamide in 300 ml. ofdimethylformamide; the temperature rose to about 50 C. and was thenmaintained for 1.5 hours at 7080 C. The cooled reaction product was thenpoured onto water, shaken with methylene chloride, washed successivelywith sodium hydroxide solution and water and, after distillation of thereadily volatile solvents, 146 g. ofN-methyl-N-a,a-difiuoro-,B,B-dichloroethyl-3,4- dichlorophenylsulfonamide were obtained. Melting point 42-43 C.

Elementary analysis.-C H Cl F NO S (molecular weight: 373). Found(percent): N, 3.8; Cl, 38.1; F, 9.6. Calculated (percent): N, 3.8; CI,38.0; F, 10.0.

EXAMPLE 8 According to the method of Example 7, 49 g. of1,l-difiuoro-1,2,2-trichloroethane were reacted with g. of the sodiumsalt of N-methyl-3-nitro 4-chlorophenyl sulfonamide in 200 ml. ofdimethylformamide to yield 84 g. of Nmethyl-N-a,ot-difluoro-}3,[3-dichloroethyl-3-nitro-4- chlorophenylsulfonamide, M.P. 45-46 C.

Elementary analysis.-C F Cl F N O S (molecular weight: 383.5). Found(percent): N, 7.8; Cl, 27.6; F, 9.7. Calculated (percent): N, 7.3; Cl,27.9; F, 9.9.

EXAMPLE 9 0.3 g. of sodium was dissolved while heating in 42.8 g. ofN-methyl-benzene sulfonamide and 30 m1. of dimethylsulfoxide were pouredthereon. Subsequently, tetrafiuoroethylene was fed in at C. whilevigorously stirring under normal pressure in such an amount that noolefin escaped throughthe succeeding bubble counter. The reaction Wascomplete after 2.5 hours. The reaction product was then placed on ice,shaken with ether, the ether solution was dried over calcium chlorideand the ether was evaporated. By distillation of the residue 47.1 g. ofN- methyl-N-tetrafluoroethyl-benzene sulfonamide were obtained. Boilingpoint: 146 C. under 13 torr.

Elementary analysis.C H F NO S (molecular weight: 271). Found (percent):C, 40.2; H, 3.5; F, 27.7; N, 5.3; S, 12.1. Calculated (percent): C,39.9; H, 3.3; F, 28.0; N, 5.2; S, 11.8.

EXAMPLE 10 g. of the sodium salt of p-toluene-sulfanilide wereintroduced into 300 ml. of dimethylformamide. 85 g. of1,1-difiuoro-1,2,2-trichloroethane were added dropwise thereto withinhalf an hour, whereupon the temperature rose to 34 C. Then thetemperature was raised and kept for 2 hours at 70-80 C. According to thework-up disclosed in Example 7, 98 g. ofN-a,oc-diflllOIO-fi,[3-dl0hl0l'0- ethyl-p-toluene-sulfanilide wereobtained.

Elementary analysis.C H Cl F NO S (molecular weight: 380). Found(percent): Cl, 19.0; F, 9.3. Calculated (percent): Cl, 18.7; F, 10.0.

EXAMPLE ll 85 g. of 1,1-difiuoro-1,2,2-trichloroethane were addeddropwise within half an hour to a solution of 106 g. of the sodium saltof N-methyl-benzene sulfonamide in 250 ml. of dimethylformamide,whereupon the temperature rose to 60 C. The mixture was heated foranother hour to 607 0 C. and the product was worked up as disclosed inExample 7. 79 g. of N-methyl-N-a,a-difiuorO-flfl-dichloroethyl-benzenesulfonamide were obtained. Boiling point: 123126 C. under 015 torr.

Elementary analysis.--C H ClF NO S (molecular weight: 304). Found(percent): Cl, 23.4; F, 11.9. Calculated (percent): Cl, 23.4; F, 12.5.

EXAMPLE 12 3 g. of powdered KOH were added to a solution of 17 g. ofN-ethyl-p-methylphenyl sulfonamide in 50 ml. of dimethylformamide andthe trifluoro-chloroethylene was fed in. The temperature rose to 73 C.;after an hour the reaction was complete. The reaction product was workedup as in Example 1. 24.5 g. of N-ethyl-N-(oz,ot,fl trifluoro-B-chloro)ethyl-p-methylbenzene sulfonamide were obtained. Boiling point: 144 C.under 1.5 torr.

5 Elementary analysis.--C H C1F NO S (molecular weight: 315.5).Calculated (percent): N, 4.4; Cl, 11.3. Found (percent): N, 4.4; Cl,11.0.

EXAMPLE 13 A stream of trifluorochloroethylene was fed into a solutionof 80 g. of N-methyl-benzene sulfonamide and 12 g. of the sodium salt ofthis sul fonamide in 220 ml. of dimethylformamide. After working up anddistillation 138.4 g. ofN-methyl-N-(a,a,,8-trifluoro-B-chloro)-ethylbenzene sulfonamide wereobtained. Boiling point: 115 C. under 1.2 torr.

Elementary analysis.-C H 'ClF NO S (molecular weight: 287.5). Calculated(percent): C, 37.6; H, 3.1; N, 4.9. Found (percent): C, 37.9; H, 3.3; N,5.0.

EXAMPLE 14 A stream of tetrafluoroethylene was fed within 4 hours at80-90 C. into a solution of 90 g. of N-methyl-benzene sulfonamide and 12g. of the sodium salt of the N-methylbenzene sulfonamide in 150 ml. ofdimethylformamide. After working up according to Example 1, 141 g. ofN-methyl N tetrafluoro-ethyl-benzene sulfonamide were obtained. Boilingpoint: 104-105" C. under 1 torr (cf. Example 9).

In the manner as set forth above the following compounds were prepared:

Melting point/ I With KOH as alkali metal.

6 We claim: 1. A compound of the formula in which R is alkyl of 1 to 18carbon atoms, phenyl, lower-alkylphenyl, halophenyl, dihalophenyl,halonitrophenyl, aminophenyl or naphthyl, R is alkyl of 1 to 18 carbonatoms, cyclohexyl, phenyl or naphthyl, X is hydrogen, fluorine, chlorineor bromine and Y is fluorine, chlorine, bromine or lower perfluoroalkyl.

2. The compound as claimed in claim 1, wherein R is alkyl of 1 to 8carbon atoms, phenyl, lower-alkylphenyl, halophenyl, dihalophenyl,halonitro-phenyl or naphthyl, R is alkyl of 1 to 12 carbon atoms,cyclohexyl, phenyl or naphthyl, X is fluorine or chlorine and Y isfluorine, chlorineor lower perfiuoroalkyl.

3. A process for the preparation of a compound of the formula RSO--NR'CF CHXY in which R is alkyl of 1 to 18 carbon atoms or an arcmaticradical of the benzene or naphthalene series, R is alkyl 'of 1 to 18carbon atoms, cyclohexyl or an aromatic radical of the benzene ornaphthalene series, X is hydrogen, fluorine, chlorine or bromine and Yis fluorine, chlorine, bromine or lower perfluoroalkyl, which comprisesreacting a compound of the formula RSO -NH-R' in which R and R are asdefined above, with a compound of the formula in which X and Y are asdefined above, with a catalytic amount of an alkaline agent at atemperature of 0 to 120 C.

4. The process as claimed in claim 3, wherein the alkaline agent issodium, potassium, sodium hydroxide or potassium hydroxide.

References Cited Jacs, vol. 72; 3646 (1950), P'ruett et al.

HENRY R. JILES, Primary Examiner S. D. WINTERS, Assistant Examiner US.Cl. X.R.

260-556 AR, 556 B, 583 GG, 561 HL, 30.8 R, 501.11, 653.1 R

